• 전자공학회논문지
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• 제50권10호
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• pp.231-238
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• 2013

본 논문은 플랫판넬 디스플레이 장치에 사용할 DC-DC 변환기의 설계에 관한 것이다. 6~14[V]의 단일 DC 전원전압으로부터 플랫 판넬 백바이어스용 -5[V] DC 전압 발생회로(Negative DC Voltage Generator)와 승압된 15[V], 23[V] DC 전압 발생회로, 그리고 강압된 3.3[V] DC를 얻기 위한 회로를 설계하였다. 또한 기준 전압원으로 사용하기 위한 밴드갭 회로와 발진기, 레벨변환기 회로, 고온보호 회로 등을 설계하였다. 제작공정은 부(-)전압으로 동작하는 회로와 기타 회로를 분리하기 위해서 트리플-웰(Triple-Well)구조가 적용된 공정 내압 30[V], 최소선폭 0.35[${\mu}m$], 2P_2M CMOS 공정을 사용하였다. 설계된 모든 회로는 시뮬레이션으로 검증하여 동작을 확인하였으며 원 칩으로 제작하여 플랫판넬 디스플레이 장치에 응용할 수 있도록 기능을 확보하였다.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.614-622
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• 2010

This paper presents a control method, which reduces the pulsating torque and DC voltage problems of a doubly fed induction generator (DFIG)-based wind turbine system. To reduce the torque and power ripple, a current control scheme consisting of a proportional integral (PI) controller is presented in a positive synchronously rotating reference frame, which is capable of providing precise current control for a rotor-side converter with separated positive and negative components. The power theory can reduce the oscillation of the DC-link voltage in the grid-side converter. In this paper, the generator model is examined, and simulation results are obtained with a 3 kW DFIG-based wind turbine system to verify the proposed control strategy.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권2호
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• pp.155-161
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• 2014

Industrial Static Var Generator (SVG) is typically applied at or near the load center to mitigate voltage fluctuation, flicker, phase unbalance, non-sine distortion or other load-related disturbance. Special attention is paid to the influence of grid voltage quality on SVG current, the non-sine distortion and unbalance of grid voltage causes not only the AC current distortion and unbalance but also the DC voltage fluctuation. In order to let the inverter voltage contain the fundamental negative sequence and harmonic component corresponding to the grid voltage, a new dual-loop control scheme is proposed to suppress the influence in this paper. The harmonic and negative sequence voltage decomposition algorithm and DC voltage control are also introduced. All these analyses can guide the practical applications. The simulation results verify the feasibility and effectiveness of the present control strategy and analyses.

• 한국정보통신학회논문지
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• 제16권10호
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• pp.2237-2246
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• 2012

본 논문에서는 구강센서를 소형화하고 제조 원가를 낮추기 위해 구강센서에서 필요로 하는 바이어스 회로를 구강센서 칩 내부에서 만들어주었다. 제안된 DC-DC 변환기 회로는 기준전류 발생기(reference current generator) 회로의 IREF를 이용하여 전압 레귤레이터(voltage regulator)에 필요한 기준전류와 바이어스 전류를 각각 공급해준다. 이들 전류가 각각의 전압 레귤레이 회로에서 해당되는 기준전압을 생성하여 부궤환(negative feedback)에 의해 목표전압을 regulation하게 된다. 그리고 기준전류가 전류 복사비(current mirror ratio)에 의해 mirroring되어 정전류인 IB0/IB1을 공급해주고, VREF 전압을 공급해주도록 설계하였다. $0.18{\mu}m$ X-ray CMOS 이미지 센서 공정을 이용하여 설계된 구강센서의 DC-DC 변환기의 출력 전압의 평균 전압, ${\sigma}$와 $4{\sigma}$는 양호한 측정 결과를 얻었다. 그리고 line-pair pattern 영상은 blurring 없이 높은 해상도 특성을 보였으며, 좋은 구강 영상을 획득하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.233-236
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• 1997

An investigation has been made of the various plasma chemistry reactions that occur in the corona discharge of an electrostatic precipitator operating in a typical flue gas. As the results of investigation, sulphur dioxide is removed principally by reactions with OH radicals to produce sulphuric acid, while nitrogen oxides are removed principally by reduction via the N radical to molecular nitrogen. If electrostatic precipitator\ulcorner used for flue gases are operated with positive voltages instead of negative dc voltages, there are significant reductions in the emission of the undesirable gases SO$_2$, NO, and NO$_2$. Thus, in this paper we design the bidirectional pulse generator for removal of flue gas, where the pulse width is more than 50[nsec] and the maximum output voltage is more than 100[kVl.

• 전력전자학회논문지
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• 제23권2호
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• pp.86-93
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• 2018

In this work, control methods and operating modes are proposed to manage standalone microgrid. A standalone microgrid generally consists of two sources, namely, battery energy storage system (BESS) and diesel generator (DG). BESS is the main source that supplies active and reactive power regardless of load conditions, whereas DG functions as an auxiliary power source. BESS operates in a constant voltage constant frequency (CVCF) control, which includes proportional-integral + resonant controller in a parallel structure. In CVCF control, the concept of fundamental positive and negative transformation is utilized to generate a three-phase sinusoidal voltage under imbalanced load condition. Operation modes of a standalone microgrid are divided into three modes, namely, normal, charge, and manual modes. To verify the standalone microgrid along with the proposed control methods, a demonstration site is constructed, which contains 115 kWh lead-acid battery bank, 50 kVA three-phase DC - AC inverter, and 50 kVA DG and controllable loads. In the CVCF control, the total harmonic distortion of output voltage is improved to 1.1% under imbalanced load. This work verifies that the standalone microgrid provides high-quality voltage, and three operation modes are performed from the experimental results.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.96-97
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• 2012

In nitride and oxide film deposition, sputtered metals react with nitrogen or oxygen gas in a vacuum chamber to form metal nitride or oxide films on a substrate. The physical properties of sputtered films (metals, oxides, and nitrides) are strongly influenced by magnetron plasma density during the deposition process. Typical target power densities on the magnetron during the deposition process are ~ (5-30) W/cm2, which gives a relatively low plasma density. The main challenge in reactive sputtering is the ability to generate a stable, arc free discharge at high plasma densities. Arcs occur due to formation of an insulating layer on the target surface caused by the re-deposition effect. One current method of generating an arc free discharge is to use the commercially available Pinnacle Plus+ Pulsed DC plasma generator manufactured by Advanced Energy Inc. This plasma generator uses a positive voltage pulse between negative pulses to attract electrons and discharge the target surface, thus preventing arc formation. However, this method can only generate low density plasma and therefore cannot allow full control of film properties. Also, after long runs ~ (1-3) hours, depends on duty cycle the stability of the reactive process is reduced due to increased probability of arc formation. Between 1995 and 1999, a new way of magnetron sputtering called HIPIMS (highly ionized pulse impulse magnetron sputtering) was developed. The main idea of this approach is to apply short ${\sim}(50-100){\mu}s$ high power pulses with a target power densities during the pulse between ~ (1-3) kW/cm2. These high power pulses generate high-density magnetron plasma that can significantly improve and control film properties. From the beginning, HIPIMS method has been applied to reactive sputtering processes for deposition of conductive and nonconductive films. However, commercially available HIPIMS plasma generators have not been able to create a stable, arc-free discharge in most reactive magnetron sputtering processes. HIPIMS plasma generators have been successfully used in reactive sputtering of nitrides for hard coating applications and for Al2O3 films. But until now there has been no HIPIMS data presented on reactive sputtering in cluster tools for semiconductors and MEMs applications. In this presentation, a new method of generating an arc free discharge for reactive HIPIMS using the new Cyprium plasma generator from Zpulser LLC will be introduced. Data (or evidence) will be presented showing that arc formation in reactive HIPIMS can be controlled without applying a positive voltage pulse between high power pulses. Arc-free reactive HIPIMS processes for sputtering AlN, TiO2, TiN and Si3N4 on the Applied Materials ENDURA 200 mm cluster tool will be presented. A direct comparison of the properties of films sputtered with the Advanced Energy Pinnacle Plus + plasma generator and the Zpulser Cyprium plasma generator will be presented.